In a case where plural types of data is sorted for each type and stored, a storage area (hereinafter, referred to as management area) storing information, which is referred to during the sorting, may be used separately from an area storing the data itself.
However, in a case where a large amount of data is processed, by preparing not only an area for storing the data itself but also a management area, the storage area of a system is occupied, which may affect the performance of other processes. In addition, in a case of a system (for example, embedded system) in which usable physical resources are limited, a process may not be performed due to an insufficient storage area. As related art of Patent Document 1, there is Japanese Laid-open Patent Publication No. 11-167508. Also, as related art of non-Patent Document 1, there is Bing-Chao Huang, Michael A. Langston, “Fast Stable Merging and Sorting in Constant Extra Space”, The Computer Journal, Oxford University Press, Dec. 1, 1992, volume 35, No. 6, pp. 643-650.